Detection, analysis and chromosome assignment of genetic autosomal linkages is the objective of this research. The methods involve three phases: (1) development of a suitable battery of test markers, which are human polymorphisms representing autosomal loci; (2) collection of appropriate blood and saliva samples from informative kindreds; and (3) statistical analysis of selected sibships for evidence of genetic linkage between a specific genetic trait and a test marker or a genetic linkage group. The investigation will be primarily directed towards families which have already been ascertained but which have not been completely studied. Families which are found to be informative for a particular linkage relationship will be extended if possible so that the most efficient linkage research will be operative. The families which are already known to be informative for Linkage Group 1 will be most intensively investigated. Although the proposal does not limit itself to searching for any specific trait, preferences will be given to families which are logistically accessible and cooperative. The direction of investigation will be guided by the positive linkage scores. BIBLIOGRAPHIC REFERENCES: Magenis, R. E., Koler, R.D., Lovrien, E.W., Bigley, R.H., Duval, M.C. and Overton, K.M.: Further evidence for the assignment of the red cell acid phosphatase gene (ACPI) to the short 0rm of chromosome 2 from gene dosage effect. National Foundation Birth Defects Original Article Series. Vol XII, No. 7:326-327 (1976). Rivas, M.L., Conneally, P.M., Lovrien, E.W., Magenis, R.E., Merritt, A.D., Meyers, D.A., Palmer, C.G., Parks, M., Wange, L., and Yu, P.L.: The linkage and mapping relationships of lgh. National Foundation Birth Defects Original Article Series, Vol XII, No. 7:347-350 (1976).